28 



Briintz found that certain small cells of the 

 epithelium of the hepatopancreas, called ' Fermentzellen ' 

 by Weber, pass coloured solutions such as acid fuchsin 

 from the body cavity into the lumen of the duct and are 

 excretory in nature. 



Reproductive Organs. 



The reproductive organs of Ligia oceanica are simple 

 in structure. In the male (PL IV., fig. 4) there are three 

 pairs of elongate fusiform testes (t.), each being prolonged 

 into a fine filament. They are situated dorsal to the 

 intestine in the second and third thoracic segments. The 

 three testes of each siide are placed in series, and open into 

 a vas deferens (v. d.) of uniform width throughout the 

 greater part of its length. The vasa deferentia are usually 

 white and extended. They are situated on the dorso- 

 lateral sides of the intestine, and extend in a horizontal 

 direction to the seventh thoracic segment. In this 

 segment they narrow abruptly to form two narrow ducts, 

 which curve ventrally round the hepatic tubules; each 

 opens at the base of a styliform appendage {st. ap.) 

 situated on the ventral side of the seventh thoracic 

 segment, on one side the median line. The testes are 

 divided by slight constrictions which indicate different 

 regions of spermatogenesis in the interior. In the 

 process of spermatogenesis the spermatids unite in varying 

 numbers to form colonies, their cell walls disappearing. 

 The nuclei elongate considerably, and very fine fibres are 

 formed which may be attached to the nuclei, but on 

 account of their extreme tenuity the writer is unable to 

 be certain on this point. Miss Nichols found the same 

 difficulty in the spermatogenesis of Oniscus asellus. The 

 whole sperm colony, as it may be termed, together with 

 the cytoplasmic fibres, is surrounded by a protoplasmic 



